Several years ago I swapped a 1UZ into my '88 'runner. I couple years of spirited driving and I grenaded my 8" e-locker axle. So I built a 35 spline Ford 9" with Explorer rear discs and a drum-in-hat parking brake. That parking brake never did work very well. It would kinda, sorta hold the truck on flat ground, but only if it was also in gear. The problem lie in trying to balance the amount of cable pulled versus the leverage - I could get it to hold, but I had to use my legs to help pull the handle (then the cable broke). So, being bored one weekend, I made a trip to the local PickNPull and grabbed a set of rear electric parking brake calipers off a VW Tiguan to play with. I tried a bunch of different rotors, but ended up keeping the Explorer rotors for now (eventually, when they're more common in the yards, I plan on switching to '20- Explorer electric calipers). Think of the EPB motor as just tightening a screw which presses against the back of the caliper piston to extend it and hold the rotor. Once that is done, there is no more electricity consumed.
Here's the simple CAD of the adapter I made. It gets sandwiched between the axle end and the bearing retainer. It's also exactly the same .350" thickness as the Explorer rear disc drum-in-hat backing plate that I used previously.
I was gonna use the VW ECU to control the calipers, but due to the circuit design, I would have HAD to use the VW switch, which I didn't want to do (and no aft mkt switch would work). I measured 12A to one caliper from the stock ECU when the caliper was activated. A 15A self-resetting circuit breaker for both calipers provides amble safety margin to prevent caliper damage while also holding the truck on any angle hill I've come across so far. Both wires to the EPB motor have ground until the SPDT momentary switch is moved to either side, then one of the relays supply power to one wire while the other wire still has ground and the motor activates. Flip the toggle the other way and the motor reverses direction. (note: 87a is normally closed, terminal 30 connects to term 87 when the coil gets power and ground, the relay pic I chose is goofy)
relays were tucked up inside the dash on a nice little bracket I made. 12ga wires were used from the self-resetting circuit breaker for power supply to the relays, and 14 ga wires from the relays to the calipers
I used a 14 gauge 4 conductor cable from the relays to the calipers (2 14 gauge wires for each caliper) from the relays to the axle, securing the wires to the rear diff breather hose
finished product. To activate, with my foot on the brake pedal, I hold the toggle switch for a count of 3 or until I feel the pedal drop slightly (indicating that the EPB is pressing the caliper piston harder than I was). To release, with my foot on the brake, I hold the toggle in the other direction for a count of 3. I used a stainless 14ga 12" pizza pan for the dust shield on the back of the rotor. Last weekend I drove several hundred miles chasing rally cars at the Oregon Trail Rally, and the calipers worked just fine (note: I already had a manual proportioning valve to dial in the brake bias split).
Here's the simple CAD of the adapter I made. It gets sandwiched between the axle end and the bearing retainer. It's also exactly the same .350" thickness as the Explorer rear disc drum-in-hat backing plate that I used previously.
I was gonna use the VW ECU to control the calipers, but due to the circuit design, I would have HAD to use the VW switch, which I didn't want to do (and no aft mkt switch would work). I measured 12A to one caliper from the stock ECU when the caliper was activated. A 15A self-resetting circuit breaker for both calipers provides amble safety margin to prevent caliper damage while also holding the truck on any angle hill I've come across so far. Both wires to the EPB motor have ground until the SPDT momentary switch is moved to either side, then one of the relays supply power to one wire while the other wire still has ground and the motor activates. Flip the toggle the other way and the motor reverses direction. (note: 87a is normally closed, terminal 30 connects to term 87 when the coil gets power and ground, the relay pic I chose is goofy)
relays were tucked up inside the dash on a nice little bracket I made. 12ga wires were used from the self-resetting circuit breaker for power supply to the relays, and 14 ga wires from the relays to the calipers
I used a 14 gauge 4 conductor cable from the relays to the calipers (2 14 gauge wires for each caliper) from the relays to the axle, securing the wires to the rear diff breather hose
finished product. To activate, with my foot on the brake pedal, I hold the toggle switch for a count of 3 or until I feel the pedal drop slightly (indicating that the EPB is pressing the caliper piston harder than I was). To release, with my foot on the brake, I hold the toggle in the other direction for a count of 3. I used a stainless 14ga 12" pizza pan for the dust shield on the back of the rotor. Last weekend I drove several hundred miles chasing rally cars at the Oregon Trail Rally, and the calipers worked just fine (note: I already had a manual proportioning valve to dial in the brake bias split).
